Travis CI unit tests are failing

[kitsook]

Unit tests run fine with docker images but failing on Travis CI. Last successful execution was a few months ago.

Last successful run: https://travis-ci.org/ubc/iPeer/builds/539427352

Failed run: https://travis-ci.org/ubc/iPeer/builds/559198094

Comparing the diff between the two commits (eefb413 vs fc4620a) doesn't show any reason why the test cases are failing. The CI env is diff though. The PHP is installed differently and is of an older version with recent runs.

The issue seems to be related to group option in CakePHP data retrieval. Using this option seems to cause the find function returns nothing. e.g. commenting this out will make the Course model tests pass on CI:

https://github.com/ubc/iPeer/blob/53bbb6290d88d4e684d49766f16b39963c8ae2aa/app/models/course.php#L483-L486

[kitsook]

With MySQL 5.7.5, the sql_mode ONLY_FULL_GROUP_BY is set. This breaks some iPeer queries.

For now, will add the followings to .travis.yml so test cases can run:

  # disable ONLY_FULL_GROUP_BY... otherwise some iPeer queries will fail
  - mysql -e "SELECT @@sql_mode;" -uroot
  - mysql -e "SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));" -uroot
  - mysql -e "SELECT @@sql_mode;" -uroot

In long run, needs to revise those queries. The way iPeer uses group to find distinct values is not complying to SQL standard.

Take extra precautions when upgrade database.